Method and apparatus for making collector brushes



Dec. 15, 1931. H, MUNDAY 1,836,385

METHOD AND APPARATUS FOR MAKING COLLECTOR BRUSHES Filed May 18, 1928 midi-(Ace i 55 I I 6'1 1N VEN TOR.

W M) A TTORNEY.

Patented Dec. 15, 1931 PAT-VENT OFFICE HORACE D. MUNDAY, OF SCHE-NECTADY,-NEW YORK METHOD,AND APPARATUS FOR MAKING COLLECTOR BRUSHES Applicationdfiled May 18,

This invention relates to the preparation of articles or bodies formed of consolidated granular or powdered material and particularly it relates to the preparation."of-brushes V1 for commutators or current collectors. More particularly it relates to the preparation of a brush formed of material whosecomposi tion differs in different parts of the brush.

In preparing brushes having uniform composit on, it has been customary to employ a mold into which are introduced the brush ingredients in the form of a .mixed powder, and after moldingto the desired shape, the contents of the mold are subjected to pressure and heat to consolidate the mass;

One object of my invention is'to provide an improved method and v apparatus for preparing a brush of Varying composition'by molding, pressing and heating.

A further object is to provide an improved method and apparatus for forming, a brush, the different parts of which vary in composition,'which brush is of strong and rigid construction, without planes of cleavage.

A further object of my invention is to provide an improved method of filling the mold with the brush ingredients and in a manner that different parts of the completed brush will have the ingredients present in diiferent proportions and wherein the proportions of the various ingredients in any part of the brush may be controlled or varied as desired.

A further object of my invention is to provide an improved method and means for mixing powder ingredients whereby mixing is easily, rapidly and continuously performed. y

In the form of my invention herein *disclosed my improved method and apparatus are employed for the manufacture of brushes composed of conducting material such as carbon or graphite and abrasive material such as carborundum or alundum; Such brushes may be employed to polish or true a commutator. In forming a brush of this composition, whereinpart of the brush is to be abra sive and part non-abrasive, I employ for the non-abrasive part a dry powderconsisting of carbonaceous material and a bmder which 1928. seriai ne. 278,755.

when pressed and heated will serve to unite" the particles of carbonaceous materiah For the abrasive part "of the brush I employ a drypowder consistingof carbona'ceousmaterial,- if such material is to be employed, abraslve material and in proper proportion'the binder above referred to. To introduce these streams, one of the abrasive powder and the other of the non-abrasive powder, these streams being so directed that they may be caused to join and mingle in whole or in part and each of the streams being independently or'simultaneously variable at the will ofthe operator from complete cessation to maximum' This control of the mixing powders into the brush mold I produce two and the volume of the streams permits the the mold being of different composition from the powder in some other "partlof the mold. The streams are preferably fedinto the mold so that the material is deposited evenly over the bottom of the'mold and the mold is filled up evenly in such away that at all times the material in the mold is of uniform depth. After the deposit of the brush powder in the mold the powder is compressed in the mold and fired to produce the proper consolidation of the particles.

To generate a stream of a brush powder. constituent, one of the brush powder'constituents, say the non-abrasive, is placed in some receptacle such as a sieve or riddle; the other brush powder constituent, say the abrasive brush powder constituent, being placed in a mold to be filled, the powder in one part of similar sieve or riddle. The two sievesor riddles are then revolved or otherwise agitated to discharge the contents in two brush powder streams, the magnitudes of said stream being varied by the speed of rotation or degreev of agitation of said sieves or rid dies from complete cessation to the maxi- 'mum possible. By gradually varying the.

Conse- The force of gravity is preferably used to keep the brush powder streams flowing, but other means may be used, such as a blast of air or the. momentum acquired when thrown Off from some rotating or moving container. Preferable means are provided such as in clined screens or bafile plates or currents of air for effecting a complete mixing of the several ingredients of the moving streams which have joined to form a single stream.

By the use of the. apparatus just described it is possible 'to deposit in one part of the mold a brush powder of one composition and in another part of the mold a brush powder of a different composition. By mixing streams of different powders and at the same time gradually-increasing the volume of one stream and decreasing the volume of the other, it is possible toform a zone between two parts of the .brush where the composition of the mixed powder varies gradually from the composition of, one part to the composition of the other part. This avoids the formation of planes of cleavage in the brush which tends to weaken the brush structure.

Other objects and advantages of my invention will appear from the following description taken in connection with the ac companying drawings wherein Figure 1 is a general perspective view of a mixing machine, a part of the casing of the discharge spout being broken away to show the mixing sieves therein;

Figure 2 is a sectional viewof the discharge spout, and brush mold;

Figure 3 is a plan view of the friction drive inone extreme position;

Figure 4 is a plan view of the friction drive in the other extreme position and Figure 5 is a perspective view of a brush made by, employing the apparatus shown in Figures 1 to 4.

In the mixing apparatus shown in F igures 1 to 5 there are two cylindrical sieves 51 and 51a secured to shafts 52 and 52a mounted in bearings 53, 53 attached to the frame 54 secured by the legs 55 to the top of a bench or other support. Under the two cylinders is the hopper 56 having side wallswhich are inclined laterally of the cylinders 51 and 51a and terminate in a discharge spout 57 which leads to the brush mold 58. Power to rotate the cylindrical sieves is received from the driving shaft 59 through the clutch 60 operated by the arm 61, then through the shaft 62 the pulley 63 the belt 64 the pulley 65 the shaft 66, the friction discs 67 the friction wheels 68 to the shafts 52 and 52a. The friction discs 67 are mounted in the upper and movable end of a swinging standard 69 swivelly secured to the bearing housing 70. The handle 71 serves for manual manipulation of the standard 69 fromthe position in 'dicated in Figure 3 tothat indicated in Figure 4, or the reverse; Doors 72eare provided in the cylindrical sieves 51 and 51a so that the brush powder-abrasive and non-abrasivemay be placed therein preparatory to mixing. A disc partition 7 3 may be provided in one or both of the cylinders about midway of its length; and if desired an abrasive brush powder may be placed on one end of one cylinder and a non-abrasive brush powder in the other end of this cylinder, and only a nonabrasive brush powder in the other cylinder. The inclined sieves or screens 74 arranged in the discharge spout 57 are for the purpose of more thoroughly interminglingthe two powder streams discharged from the two cylinders; there being however little tendency for the brush powder streams discharge from the two halves ofa divided cylinder to intermingle, except at their boundary line.

In filling the mold by means of the apparatus shown in Figures 1 to 4 with a view to forming the brush shown in Figure 5 one part such as one ounce of abrasive brush powder of the desired composition placed inthe front compartment of the cylindrical sieve 51a, one part of non-abrasive brush powder in the rear compartment of cylinder 51a, and two parts of non-abrasive brush powder in cylinder 51. The initial position ofthe friction discs and friction wheels will be as shown in Figure 4. Power to rotate the cylinders is applied by operating the clutch 60. When nearly all the abrasive brush powder is, out, of the front compartment of cylinder 51a the standard 69 is swung backwards until friction discs and friction wheels are in the position shown in Figure 3; this position being maintained until all the nonabrasive powder has escaped from cylinder When sufficient powder has been introduced intothe mold to form a brush of the desired thickness, the mold is transferred to a press and by means of a plunger the powder is compressed. The brush is then removed from the mold and fired.

In order to vary the speed of rotation of one of the cylinders 51 and 51a independently of the other the friction wheels 68 may be mounted on their respective shafts so that they'may be adjusted longitudinally of the shafts, thus the wheels 68 may be keyed to the shaftsand adjustable means provided for rigidly securing the wheel to the shaft, after it has been adjusted to the desired position along the shaft.

I claim:

1. In a mixing and. delivering apparatus, receptacles for containing divided materials, means for causing said materials to be delivered from said receptacles inthe form of streams, means for causing said streams to join to form a combined stream and means for varying, independent, of the quantities of material in said receptacles, the relative rate in which material of the said streams enter the combined stream and consequently the percentage of the material 'in' successive cross sections of thecombinedlstream. f

means for causing said'materials to be dellvered from sald receptacles 1n the form of streams, means for causing said streams to join to form a combined stream, meanstfor- 'varylng independent of the quantities of material in thesaid receptacles, the relative rate at which materials of the several streams enter the combined stream and consequently the percentage of the material in successive cross sections of the combined stream and means for mixing the material of the stream so asto produce a combined stream of homogeneous cross-sectional composition.

3.'In a mixing and delivering apparatus for divided materials, a plurality of perforated cylinders for containing the materials to be mixed, means for rotating the cylinders to cause the materials to be delivered therefrom in the form of streams, means for varying the speed of rotation of said cylinder so as to control the volume of the streams delivered and means for causing stream from a plurality of cylinders toaj oin so as, to form a combined stream.

4. In a mixing and delivering apparatus for divided materials, a plurality of perforated cylinders for containing the materials to be mixed, means for rotating the cylinders to cause the materials to be delivered therefrom in the form of streams, means for varying the speed of rotation of said cylinders so as to control the volumes of the stream delivered therefrom, mean for causing streams from a plurality of cylinders to join so as to form a combined stream and means for mixing the moving materials of said combined stream. 7

5. In a mixing and delivering apparatus for divided materials a plurality of perforated cylinders for containing the materials to be mixed, means for rotating the cylinders to cause the materials to be delivered therefrom in the form of streams, means for varying the speed of rotation of saidcylinders so as to control the volumes of the streams delivered therefrom, means for causing streams from a plurality of cylinders to join so as to form a combined stream and screens inter posed in the path of said combined stream for mixing the moving material of said combined stream.

6. The method of forming an article of plurality of ingredients which are to be present in different proportions indifferent parts of the article which methodconsists in forming uniform mixtures of powdered ingredients, different mixtures having different composition and each of the mixtures containing a material which when pressed and heated will form a binder, introducing the material of said mixtures intoa mold by forming separate mixtures into separate I l streams, causing certain'of said streams to 2. Ina imixingiand delivering apparatus, receptacles for cont'ammgdwided materlals,

join soas to form a combinedistreain and simultaneously varying the volume of" said certain streams, therebyvarying the com position of said. combined stream and ress ingandeheatingsthe material so intro uced into said mold. a v 7. The method of forming an articleof a plurality ofingredients which are to be present in difierent proportions in difierent parts of the article, which method consists in form ing uniform mixtures *of powdered ingredients, different mixtures having difierent composition and each'of the mixtures con-' taining a materialwhich when pressed or heated will form a binder, introducing the material of said, mixtures into a mold by formingsaid mixtures into separate streams, directing diflerent streams to different parts I of 'themold, causing certain of said streams tojoin so as to form a combined stream and simultaneously varying the volume of said certain streams whereby the compositionof said combined: stream is varied and pressing and heating the material so introduced: into the mold. y i

8. A step in a method of forming abrush i i of non-uniform composition by molding and firing, which step} consists in forming ,a

firing, which step consists in forming a,

stream of evenly falling granular or powdered material, the composition of the stream being different at different parts of the cross-- section thereof and directing said stream into a mold through the top thereof, whereby ,the. material is continually deposited onthe bot-e, tom of the mold as an even layer, different" parts of which have different composition.

10. The method of forming acollector brush of non-uniform composition which consists in forming a stream of evenly falling granular or powdered material, the composition O-llh6 stream being different at dif ferent parts of the cross-section thereof, di-: recting said stream into a mold through the top thereof, whereby the material is continu ally deposited as an even layer on the bottom of the mold, compressing the material so deposited from the top thereof and firing a compressedmaterial. y l

11. The method of forming an abrasive collector brush of non-uniform abrasive content which consists in forming uniformmixturesof powdered ingredients, different mixwhich when pressed or heated will form a binder, introducing the material of said mixtures into a mold by forming separate mixtures into separate streams, causing certain of said streams to join so as to form a combined stream-and simultaneously varying the volume of said certain streams, whereby the composition of said combined stream is varied, compressing the material in said mold a, spout adapted to receive material from said hopper and means for mixing materials from separate cylinders, said means comprising an inclined screen located in the path of material passing through said spout.

16. A step in a method of forming a brush of non-uniform composition by molding and firing, which step consists in forming a stream of granular or powdered material, the composition of the stream being different at different cross-sections thereof and directing said stream into a mold through the top thereof.

Signed at New York, in the county of New of May, A. D. 1928.

HORACE D. MUNDAY.

York and State of New York, this 17th day mymixtures into separate streams, directing at different streams to difierent parts of the mold, causing certain of said streams to join so as to form a combined stream and simultaneously varying the volume of said certain -streams, whereby the composition of said 90 combined stream is varied, compressing the material in said mold and heating the compressed material.

13. A mixing machine or apparatus, comprising means for holding separately two or more brush powder constituents, means of discharging from either or all holders or containers a brush powder constituent stream or streams, either at a rate of flow fixed in sm'magnitude or continually or intermittently varying at the will of the operator, means of combining said streams into one stream, means of receiving and holding as in a mold said combined streams or one brush powder 40 constituent stream, and means of evenly distributing the falling powder over the floor of said mold.

14. A mixing machine or apparatus, comprising two holders or containers for holding 'iseparately two brush powder constituents, means for discharging from said containers portions of the said constituents at separate time intervals and the remaining portions simultaneously, the latter portions at a controllably varying proportionality in the relative magnitude of the discharges or streams, means of combining the two brush powder streams into one brush powder stream, and means of receiving and holding the said one lstream in a receptacle or mold, and means of evenly distributing the falling brush powder over the fioor of the mold.

15. In a mixing and delivering apparatus, a plurality of perforated cylinders rotatably Imounted side by side, a hopper located beneath said cylinders and adapted to receive materials passing from said cylinders through the perforations thereof, said hopper having side walls which are downwardly i11- iclined in .a direction lateral to said cylinder, 130 

